Rock drill



E. G. GARTIN Dec. 27, 1-932.

ROCK DRILL Filed Jan. 17. 1929 Iwenfow;

W may a. Z

Patented Dec. 27, 1932 UNITED STATES PATENT OFFICE I ELMEB, G. GAR'IIN,OF ,CLAREMONT, NEW HAMPSHIRE, ASSIGNOR TO SULLIVAN i MACHINERY COMPANY,A CORPORATION OF MASSACHUSETTS w R001: DRILL Applieation flled'l'anuary17, 1929. Serial No. 333,155.

My invention relates to rock drills, and particularly to power feedingmeans for rock drills. I I

It is an object of my invention toprovide an, improved rock drillfeeding means. A

further object is to provide improved retaining means for holding a pairof telescoping members in relatively fixed position. Still anotherobject is to provide improved rock drill feeding mechanism of thecylinder and piston type having improved means for retaining thecylinder and piston in collapsed position. A more specific object is toprovide improved retaining means for holding a feed cylinder and pistonin collapsed position wherein there is also provided means for supplyingpressure fluid to the total area of the piston for effecting feedingmovement when desired. Other objects and advantages of the inventionwill hereinafter more fully a pear.

In a common type of fluid actuated feeding mechanism for rock drillseither the feed piston or feed cylinder is attached to the drillingmechanism and the other element is arranged to telescope freely relativeto the drilling mechanism. When the drill is carried from one place toanother, it is desirableto retain this freely movable member in fixedrelation and preferably retain the same in collapsed position so as tomake the machine as short as possible.- In one preferred embodiment minvention assumes the form of a sleeve pro ecting into the feed cylinderattached to the drilling mechanism having passage means through the wallof such sleeve and around the end thereof for admitting pressure fluiddirectly to the piston around the sleeve. The retaining device per se ina preferred embodiment comprises a spring ring engaging in the bore ofthe sleeve referred to above.- Obviously, however, this construction maybe extensively modified in its details within the purview of myinvention.

In the accompanying drawing 1- have shown for purposes of illustrationtwo forms which my invention may assume in practice.

In the drawing,

Fig. 1 is a plan view of a common form of stoper rock drill with whichmy invention is useful.

Fig. 2 shows a central longitudinal section through a feeding mechanismfor a stoper drill having my invention incorporated there- 55.

with in an illustrative embodiment.

Fig. 3 is a fragmentary detail view showing a modification.

Fig. 4 is a detail perspective view of the spring ring retainer.

The drilling mechanism illustrated in'Fig. 1 is of a common type havinga hammer mechanism 5 for percussively actuating a drill steel 6 mountedin a suitable chuck 7. The

power operated feeding mechanism for this drill has a cylinder member 8attached to the drilling mechanism 5 by a plurality of bolts 9 passingthrough lateral lugs 10 formed integral with the cylinder. Pressurefluid for actuating the percussive drill and the feeding mechanism issupplied through a hose connection 1.1 and suitable throttle valvemechanism 12 controlled'by the operator, with a rotatable handle 13.Supply of fluid to the feed cylinder is further controlled directly by aplunger valve having an operating button indicated at 14. The feedpiston is attached to the upper end of a piston rod 15 which atits'lower end carries a pointed abutment 16 and the piston is hereinconstructed of a plurality of resilient packing washers 17 and 18mounted between metal washers 19, 20 and 21, these washers being securedin position on the piston rod by means of a suitable retaining nut 22threaded on a reduced end of the piston rod. One of the packing washers17 is held expanded against the cylinder by pressure fluid suppliedthrough passages 23 and 24 in the piston rod and passages 25 in washer20. A sleeve member 26 is fitted into the end of the cylinder bore andhas a reduced end 27. A series of holes 28 are bored through this reduced end so that pressure fluid may pass through the sleeve and aroundthe end thereof to act on the feed piston. The packing retainer nut 22has an annular groove 29 formed therein which receives a spring ringretaining device 30 adapted to engage the internal bore of sleeve 26. Ina practical embodiment of the invention the spring ring has an outersurface 31 of spherical contour and holds the feed piston in collapsedposition merely by frictional engagement with the bore of sleeve 26.However, if desired, in order to secure a more nearly positive look agroove 32 may be cut into the sleeve, this modificationbeing'illustrated in Fig. 3. The groove is preferably of curvedformation to lit the outer surface of the spring ring. The end of sleeve26 has a beveled or curved surface 33 which is adapted to cooperate withthe outer surface of the spring ring when the piston is moved into thecylinder to contract the ring so that it will fit into the sleeve.

The operation and use of my invention will i be readily apparent in viewof the above de scription. When it is desired to carry-the drill fromone place to another, the fluid is exhausted from the feed cylinder andthe feed piston moved into the collapsed position. The spring retainingring 30 engages the bore of. sleeve 26 and holds the piston inthisposition. lVhen the machine is set up ready to drill, pressure fluid isadmitted to the feed cylinder under the control of plunger 14 and actson the total surface of the piston since it is permitted to flowimmediately through passages 28 and around-the reduced end of sleeve 26directly to the piston. This pressure is suflicient to release theretaining device immediately and effect the desired feeding movement.

While I have in this application specifically described two forms whichmy invention may assume in practice, it will be understood that theseforms of the same are shown for purposes of illustration and that theinvention may be modified and embodied in various other forms withoutdeparting from its spirit or the scope of the appended claims.

Vi hat I claim as newand desire to secure by Letters Patent is:

1. In a rock drilling apparatus, a rock drill, fluid actuated feedingmechanism therefor comprising telescoping cylinder and piston elements,means forretaining said elements in collapsed position comprising asleeve projecting into said cylinder, a retaining device carried by saidpiston for engaging said sleeve to hold the piston and cylinder incollapsed position, and passage means extending latorally through thewall of said sleeve and around the end thereof for supplying fluid tosaid piston for moving the same thereby to release said retaining meansand effect feeding movement.

2. In a fluid actuated feeding mechanism for rock drills, a feedcylinder, a piston and piston rod reciprocable therein, means forretaining said piston and cylinder in collapsed position comprising areduced extension projecting upwardly from the piston, a sleeveprojecting into the cylinder, yielding means carried by said reducedextensionfor frictionally engaging the bore of said sleeve,

and means including radially extending passages in said sleeve forsupplying pressure fluid around said yielding means to said piston.

3. A fluid actuated feeding mechanism for rock-drills comprising a feedcylinder, a feed piston and piston rod reciprocable in said cylinder, asleeve projecting into one end of said cylinder and having a reducedouter end, means carried-by said piston for frictionally engaging saidsleeve to hold the cylinder and piston in collapsed relation, and meansincluding passages in said sleeve member forsupplying pressure fluidthrough the latter and around said reduced end to the piston for movingthe same thereby to release said retaining .means and effect feedingmovement.

4. Afluid' actuated feeding mechanism for rock drills comprisingtelescoping cylinder and piston elements, a reduced extension on saidpiston element projecting beyond the piston,.a sleeve projecting intothe end of said cylinder element, a spring ring carried by said reducedextension and'receivable in said sleeve when the cylinder and piston arein collapsed position, said ring frictionally engaging said sleeve toyieldingly hold said piston and cylinder in such position,- and meansincluding passages extending laterally through said sleeve for supplyingpressure fluid to the'total area of said piston for moving the samethereby to release said spring ring retainerand eflect feeding movementon supply of pressure fluidto the bore of said sleeve.

5. A fluid actuated feeding mechanism for rock drills comprisingtelescoping cylinder and piston elements, a reduced extension on saidpiston element projecting beyond the piston, said piston having an areapresenting a surface on which feeding pressure fluid may act tosupplement-the action of pressure on the end of said extension, a sleeveprojecting into the end of said cylinder element, a spring ring carriedby said reduced extension receivable in the bore of said sleeve andbearing against the wall of said sleeve for frictionally holding thepiston in fixed relation with the cylinder, and means, operative uponthe admission of feeding pressure fluid to the interiorof said. sleeveto act upon the end of said reduced extension, andiwhile said ring stilllies within said-sleeve, to conduct feeding pressure fluid distinct fromany leakage past said ring, to said surface.

6. A'fluid actuated feeding mechanism for rock drills comprisingtelescoping cylinder and piston elements, one of said elements having aprojecting portion providing a surface upon which pressure fluid may actto provide a feeding pressure,the effective area of such surface beingless than the full cross sectional area of the piston, and said elementalso providing another surface upon which'pres'sure fluid may act toprovide a feeding pressure, the effective area of said last mentionedsurface being substantially equal to the difference between the fullcross sectional area of the piston and the effective area of saidprojecting portion, the other of said elements having a portion forminga chamber to receive said projecting portion and cooperating, when saidportions are in telescoped relation, with the proj ecting portionsubstantially to partition off one of said surfaces from the other,releasable locking means carried by one of said portions and cooperatingwith the other when said portions are in telescoped relation to holdsaid elements in collapsed position and acting to augment thepartitioning action aforesaid, feeding pressure fluid supply meansoperative to supply feeding pressure fluid directly only to one of saidsurfaces when said portions are in telescoped relation, and meansoperative upon admission of feeding pressure directly to said lastmentioned surface and While said portions are in telescoped relation, toconduct feeding pressure fluid distinct from any leakage past saidreleasable locking means, to the other of said surfaces.

In testimony whereof I aflix my signature.

ELMER Gr. GARTIN.

